The present invention relates to the stabilization of marine oils. More particularly of fully or partially refined marine oils.
Marine oils have attracted substantial interest as a source of long-chain polyunsaturated fatty acids, particularly eicosapentaenoic acid (EPA), docosapentsenoic acid (DPA) and docosahexaenoic acid (DHA), which are considered to be of dietary significance. These fatty acids contain 5 or 6 double bonds, which render them prone to atmospheric oxidation. It is believed that the peroxides produced in this oxidation break down to secondary oxidation products, which exhibit a pronounced taste and smell of fish.
It has been known for a long time that refined marine oil is initially free from a taste and smell of fish, but that reversion through oxidation occurs rapidly. Attempts have been made to stabilize the oil by the addition of .alpha.-tocopherol or mixed tocopherols at a level of 0.1%, but this has resulted only in a short term improvement in stability, i.e. a few days. Stabilization with tetrabutylhydroquinone has also been proposed, but this is of very restricted application having regard to the extremely bitter taste of this compound.
There has accordingly been a need for a process by means of which such marine oil can be stabilized over a long period in a simple and economical manner.